Guide to UHECR Public Data

The era of open science has transformed cosmic ray research. Major observatories now release their data publicly, enabling anyone — students, citizen scientists, independent researchers — to explore the universe's most energetic particles. Here's your complete guide to finding and using this data.

Pierre Auger Open Data

The Pierre Auger Observatory released its first public dataset in 2021, marking a milestone for open science in astroparticle physics.

What's Available

Website: opendata.auger.org

• 10% cosmic ray sample: ~22,000 events from 2004-2018 above 10¹⁸ eV
• DOI: 10.5281/zenodo.4487613
• 100% atmospheric data: Weather, aerosols, cloud coverage through 2020
• Space weather data: Scaler rates for monitoring cosmic ray flux variations
• Highest-energy catalog: 100 events above 52 EeV (DOI: 10.5281/zenodo.6867688)

Data Format

Cosmic ray events are provided in JSON format with fields including:

Getting Started

1. Visit opendata.auger.org
2. Navigate to "Cosmic ray data" → "10% data release"
3. Download JSON files directly or use the provided Jupyter notebooks
4. The site includes Python tutorials for basic analysis

Analysis Ideas

• Plot the energy spectrum and identify features (ankle, suppression)
• Create sky maps of arrival directions
• Search for anisotropies or clustering
• Study zenith angle distributions
• Correlate with external catalogs (AGN, starburst galaxies)

GWOSC: Gravitational Wave Data

The Gravitational Wave Open Science Center provides all LIGO/Virgo/KAGRA data for multi-messenger studies.

What's Available

Website: gwosc.org

• Strain data: Raw gravitational wave detector output
• Event catalogs: GWTC-1, GWTC-2, GWTC-2.1, GWTC-3, GWTC-4.0
• 200+ detections: Binary black holes, neutron star mergers
• Parameter estimates: Masses, spins, distances, sky localizations
• Tutorials: Python notebooks for signal analysis

Key Catalogs

For UHECR Correlation Studies

The most useful GWOSC products for UHECR research:

• Event times: GPS timestamps for temporal correlation
• Sky maps: Probability distributions for source location
• Distance estimates: Luminosity distance with uncertainties
• Source classification: BBH, BNS, NSBH

Download parameter estimation files (posterior samples) for detailed source properties.

Fermi GBM Burst Catalog

The Fermi Gamma-ray Burst Monitor has detected over 3,500 gamma-ray bursts since 2008.

What's Available

Website: HEASARC Fermi GBM Catalog

• Burst positions: RA/Dec with error circles
• Timing: Trigger time, T90 duration
• Fluence: Energy flux in different bands
• Classification: Long vs. short
• Light curves: Time-resolved flux data

Accessing the Data

Use the HEASARC Browse interface to query the catalog. You can filter by date range, duration, position, and other parameters. Results can be downloaded in various formats (FITS, CSV, VOTable).

IceCube Data Releases

IceCube has released several datasets of high-energy neutrino events.

What's Available

Website: icecube.wisc.edu/science/data-releases

• Point source samples: Track-like events with good angular resolution
• Cascade events: All-flavor neutrino sample
• High-energy starting events (HESE): The highest-energy neutrinos
• Alert events: Real-time high-significance detections

Multi-Messenger Potential

Neutrinos travel in straight lines and arrive without delay (like light). Finding neutrino-UHECR correlations would strongly constrain common sources.

KASCADE Cosmic Ray Data Centre

KASCADE and KASCADE-Grande operated in Germany from 1996-2013, detecting cosmic rays from 10¹⁵ to 10¹⁸ eV.

What's Available

Website: kcdc.iap.kit.edu

• ~500 million events: Extensive database
• Detailed shower parameters: Core position, electron/muon numbers, age
• Multiple quality cuts: Different selection criteria
• Documentation: Extensive user guides

Energy Range

KASCADE covers lower energies than Auger — the "knee" region. Useful for understanding the galactic-extragalactic transition and calibrating composition methods.

Zenodo: General Repository

Many research groups deposit supplementary data on Zenodo, CERN's open data repository.

Website: zenodo.org

Search for: "cosmic rays," "UHECR," "Pierre Auger," "Telescope Array," etc. You'll find simulation datasets, analysis code, and supplementary materials from published papers.

Tools for Analysis

Python Libraries

• astropy: Coordinate transformations, time handling
• healpy: HEALPix sky maps
• numpy/scipy: Numerical analysis
• matplotlib: Visualization
• pandas: Data manipulation

Coordinate Systems

UHECR analysis requires fluency with multiple coordinate systems:

• Local (zenith/azimuth): Detector-centered
• Equatorial (RA/Dec): Sky coordinates, J2000 epoch
• Galactic (l, b): Centered on Galactic Center
• Supergalactic (SGL, SGB): Aligned with local large-scale structure

Astropy's SkyCoord class handles conversions elegantly.

Example Code

import json
import numpy as np
from astropy.coordinates import SkyCoord
import astropy.units as u

# Load Auger data
with open('auger_10percent.json') as f:
    events = json.load(f)

# Convert to SkyCoord
coords = SkyCoord(
    ra=[e['ra'] for e in events] * u.deg,
    dec=[e['dec'] for e in events] * u.deg,
    frame='icrs'
)

# Transform to Galactic
gal = coords.galactic
print(f"Galactic l: {gal.l}")
print(f"Galactic b: {gal.b}")

# Filter by energy
high_e = [e for e in events if e['energy'] > 50]
print(f"Events above 50 EeV: {len(high_e)}")
            

Tips for Success

Start Simple

Begin by reproducing known results — the energy spectrum, sky maps, basic anisotropy searches. This validates your analysis pipeline before attempting novel studies.

Understand Systematics

Public datasets have limitations:

• Exposure isn't uniform across the sky
• Energy resolution smears features
• Selection effects bias distributions

The Auger open data documentation discusses these carefully — read it!

Use the Community

• GWOSC has active tutorials and support
• Many analysis codes are shared on GitHub
• ArXiv papers often include analysis details

The Power of Open Data

Public cosmic ray data enables:

• Verification: Independent checks of published results
• Education: Students can work with real data
• Discovery: Fresh perspectives might find what experts missed
• Cross-correlation: Combining datasets from different experiments

The universe's secrets are hidden in this data. The tools to find them are available to everyone.